Survey of potential carbon dioxide storage site
16 September 2008
A seismic survey of the subsurface has been initiated at the Troll field in the North Sea to determine whether the site is suitable for storage of large volumes of carbon dioxide (CO2) from carbon capture facilities at the industrial plants at Mongstad and Kårstø.
The Norwegian Petroleum Directorate (NPD) and Gassnova SF have ordered 3D-seismics to survey whether the Johansen formation at Troll is suitable for permanent storage of CO2 . StatoilHydro is responsible for the seismic data acquisition, and is using the vessel M/V Ramform Challenger, owned by PGS, for this activity.
Gassnova, the state-owned enterprise for handling CO2, is responsible for implementing the Government's carbon capture and storage (CCS) project for CO2 from Mongstad and Kårstø.
Another objective of the survey is to determine where the CO2 injection wells should be located.
”The survey is an important part of our work to achieve the goal of storing carbon dioxide in the subsurface," said Odd Magne Mathiassen, research coordinator in the NPD. Mathiassen pointed out that "finding the optimal placement of injection wells is important to ensure that the carbon dioxide can be stored and that it will remain in the reservoir in the future.”
”We have great expectations for the Johansen formation as a storage site for carbon dioxide," said Karl Erik Karlsen, Gassnova's project manager.
The NPD has studied three potential storage sites for CO2 – the Johansen formation and two potential storage sites connected to the Utsira formation in the Sleipner area.
The Johansen formation is located south of the Troll area in the North Sea at a depth of approximately 2500 metres, below the Troll oil and gas reservoirs.
The plan calls for the acquisition activity to get underway sometime in September.
3D-seismic surveys are used to map the subsurface. They take place by means of the vessel transmitting pressure waves down into the subsurface. These waves are reflected back when they encounter interfaces between different layers of rock, and these reflections are captured by long cables towed behind the vessel. Seismic experts can interpret these signals to form an image of the conditions in the subsurface.
Processing and interpretation of the 3D-seismic data will probably be completed early in 2009.